287 lines
8.5 KiB
C
287 lines
8.5 KiB
C
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/*
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* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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#ifndef CAR_H
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#define CAR_H
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// This is a fun demo that shows off the wheel joint
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class Car : public Test
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{
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public:
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Car()
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{
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m_hz = 4.0f;
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m_zeta = 0.7f;
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m_speed = 50.0f;
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b2Body* ground = NULL;
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{
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b2BodyDef bd;
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ground = m_world->CreateBody(&bd);
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b2EdgeShape shape;
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b2FixtureDef fd;
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fd.shape = &shape;
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fd.density = 0.0f;
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fd.friction = 0.6f;
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shape.Set(b2Vec2(-20.0f, 0.0f), b2Vec2(20.0f, 0.0f));
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ground->CreateFixture(&fd);
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float32 hs[10] = {0.25f, 1.0f, 4.0f, 0.0f, 0.0f, -1.0f, -2.0f, -2.0f, -1.25f, 0.0f};
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float32 x = 20.0f, y1 = 0.0f, dx = 5.0f;
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for (int32 i = 0; i < 10; ++i)
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{
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float32 y2 = hs[i];
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shape.Set(b2Vec2(x, y1), b2Vec2(x + dx, y2));
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ground->CreateFixture(&fd);
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y1 = y2;
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x += dx;
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}
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for (int32 i = 0; i < 10; ++i)
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{
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float32 y2 = hs[i];
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shape.Set(b2Vec2(x, y1), b2Vec2(x + dx, y2));
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ground->CreateFixture(&fd);
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y1 = y2;
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x += dx;
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}
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shape.Set(b2Vec2(x, 0.0f), b2Vec2(x + 40.0f, 0.0f));
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ground->CreateFixture(&fd);
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x += 80.0f;
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shape.Set(b2Vec2(x, 0.0f), b2Vec2(x + 40.0f, 0.0f));
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ground->CreateFixture(&fd);
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x += 40.0f;
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shape.Set(b2Vec2(x, 0.0f), b2Vec2(x + 10.0f, 5.0f));
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ground->CreateFixture(&fd);
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x += 20.0f;
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shape.Set(b2Vec2(x, 0.0f), b2Vec2(x + 40.0f, 0.0f));
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ground->CreateFixture(&fd);
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x += 40.0f;
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shape.Set(b2Vec2(x, 0.0f), b2Vec2(x, 20.0f));
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ground->CreateFixture(&fd);
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}
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// Teeter
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{
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b2BodyDef bd;
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bd.position.Set(140.0f, 1.0f);
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bd.type = b2_dynamicBody;
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b2Body* body = m_world->CreateBody(&bd);
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b2PolygonShape box;
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box.SetAsBox(10.0f, 0.25f);
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body->CreateFixture(&box, 1.0f);
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b2RevoluteJointDef jd;
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jd.Initialize(ground, body, body->GetPosition());
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jd.lowerAngle = -8.0f * b2_pi / 180.0f;
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jd.upperAngle = 8.0f * b2_pi / 180.0f;
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jd.enableLimit = true;
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m_world->CreateJoint(&jd);
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body->ApplyAngularImpulse(100.0f);
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}
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// Bridge
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{
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int32 N = 20;
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b2PolygonShape shape;
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shape.SetAsBox(1.0f, 0.125f);
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b2FixtureDef fd;
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fd.shape = &shape;
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fd.density = 1.0f;
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fd.friction = 0.6f;
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b2RevoluteJointDef jd;
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b2Body* prevBody = ground;
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for (int32 i = 0; i < N; ++i)
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{
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b2BodyDef bd;
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bd.type = b2_dynamicBody;
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bd.position.Set(161.0f + 2.0f * i, -0.125f);
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b2Body* body = m_world->CreateBody(&bd);
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body->CreateFixture(&fd);
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b2Vec2 anchor(160.0f + 2.0f * i, -0.125f);
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jd.Initialize(prevBody, body, anchor);
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m_world->CreateJoint(&jd);
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prevBody = body;
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}
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b2Vec2 anchor(160.0f + 2.0f * N, -0.125f);
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jd.Initialize(prevBody, ground, anchor);
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m_world->CreateJoint(&jd);
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}
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// Boxes
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{
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b2PolygonShape box;
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box.SetAsBox(0.5f, 0.5f);
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b2Body* body = NULL;
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b2BodyDef bd;
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bd.type = b2_dynamicBody;
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bd.position.Set(230.0f, 0.5f);
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body = m_world->CreateBody(&bd);
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body->CreateFixture(&box, 0.5f);
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bd.position.Set(230.0f, 1.5f);
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body = m_world->CreateBody(&bd);
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body->CreateFixture(&box, 0.5f);
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bd.position.Set(230.0f, 2.5f);
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body = m_world->CreateBody(&bd);
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body->CreateFixture(&box, 0.5f);
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bd.position.Set(230.0f, 3.5f);
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body = m_world->CreateBody(&bd);
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body->CreateFixture(&box, 0.5f);
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bd.position.Set(230.0f, 4.5f);
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body = m_world->CreateBody(&bd);
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body->CreateFixture(&box, 0.5f);
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}
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// Car
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{
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b2PolygonShape chassis;
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b2Vec2 vertices[8];
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vertices[0].Set(-1.5f, -0.5f);
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vertices[1].Set(1.5f, -0.5f);
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vertices[2].Set(1.5f, 0.0f);
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vertices[3].Set(0.0f, 0.9f);
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vertices[4].Set(-1.15f, 0.9f);
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vertices[5].Set(-1.5f, 0.2f);
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chassis.Set(vertices, 6);
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b2CircleShape circle;
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circle.m_radius = 0.4f;
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b2BodyDef bd;
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bd.type = b2_dynamicBody;
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bd.position.Set(0.0f, 1.0f);
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m_car = m_world->CreateBody(&bd);
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m_car->CreateFixture(&chassis, 1.0f);
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b2FixtureDef fd;
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fd.shape = &circle;
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fd.density = 1.0f;
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fd.friction = 0.9f;
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bd.position.Set(-1.0f, 0.35f);
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m_wheel1 = m_world->CreateBody(&bd);
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m_wheel1->CreateFixture(&fd);
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bd.position.Set(1.0f, 0.4f);
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m_wheel2 = m_world->CreateBody(&bd);
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m_wheel2->CreateFixture(&fd);
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b2WheelJointDef jd;
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b2Vec2 axis(0.0f, 1.0f);
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jd.Initialize(m_car, m_wheel1, m_wheel1->GetPosition(), axis);
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jd.motorSpeed = 0.0f;
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jd.maxMotorTorque = 20.0f;
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jd.enableMotor = true;
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jd.frequencyHz = m_hz;
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jd.dampingRatio = m_zeta;
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m_spring1 = (b2WheelJoint*)m_world->CreateJoint(&jd);
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jd.Initialize(m_car, m_wheel2, m_wheel2->GetPosition(), axis);
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jd.motorSpeed = 0.0f;
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jd.maxMotorTorque = 10.0f;
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jd.enableMotor = false;
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jd.frequencyHz = m_hz;
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jd.dampingRatio = m_zeta;
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m_spring2 = (b2WheelJoint*)m_world->CreateJoint(&jd);
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}
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}
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void Keyboard(unsigned char key)
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{
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switch (key)
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{
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case 'a':
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m_spring1->SetMotorSpeed(m_speed);
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break;
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case 's':
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m_spring1->SetMotorSpeed(0.0f);
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break;
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case 'd':
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m_spring1->SetMotorSpeed(-m_speed);
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break;
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case 'q':
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m_hz = b2Max(0.0f, m_hz - 1.0f);
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m_spring1->SetSpringFrequencyHz(m_hz);
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m_spring2->SetSpringFrequencyHz(m_hz);
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break;
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case 'e':
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m_hz += 1.0f;
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m_spring1->SetSpringFrequencyHz(m_hz);
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m_spring2->SetSpringFrequencyHz(m_hz);
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break;
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}
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}
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void Step(Settings* settings)
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{
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m_debugDraw.DrawString(5, m_textLine, "Keys: left = a, brake = s, right = d, hz down = q, hz up = e");
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m_textLine += 15;
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m_debugDraw.DrawString(5, m_textLine, "frequency = %g hz, damping ratio = %g", m_hz, m_zeta);
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m_textLine += 15;
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settings->viewCenter.x = m_car->GetPosition().x;
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Test::Step(settings);
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}
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static Test* Create()
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{
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return new Car;
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}
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b2Body* m_car;
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b2Body* m_wheel1;
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b2Body* m_wheel2;
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float32 m_hz;
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float32 m_zeta;
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float32 m_speed;
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b2WheelJoint* m_spring1;
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b2WheelJoint* m_spring2;
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};
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#endif
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